Content reproduction apparatus

ABSTRACT

A content reproduction apparatus includes a CPU  18 , and the CPU measures a power-on time period Ton, which is from a point of time that a main power switch  42  is turned-on until a point of time that it is turned-off, and a power-off time period Toff, which is from a point of time that the main power switch  42  is turned-off until a point of time that it is turned-on once again. Furthermore, a total sum T of the measured time periods Ton and Toff is evaluated, and the audio data is rendered invalid (not reproducible) when the evaluated total sum T exceeds a term of validity Ta of the audio data recorded in a memory card  12.

TECHNICAL FIELD

The present invention relates to a content reproduction apparatus forreproducing a content such as music, an image and so on. Morespecifically, the present invention relates to a content reproductionapparatus for reproducing a content having a term of validity.

PRIOR ART

In such a kind of a conventional content reproduction apparatus, a termof validity of a content is managed by taking advantage of a calendarfunction that the apparatus itself owns. That is, a date of the calendarof the apparatus itself and the term of validity of the content areverified, thereby invalidating (rendering not producible) the contentwhen the date of the calendar of the apparatus itself elapses the termof validity of the content.

However, the date of the calendar of the apparatus itself can be set toan arbitrary date so that the content becomes reproducible if the dateof the calendar of the apparatus itself is changed to a date within arelevant term of validity. Therefore, this gave rise to a problem thatit is not possible to securely prevent an illegitimate use of thecontent having an elapsed term of validity in the above-described priorart, in which the term of validity of the content is managed by takingadvantage of the date of the calendar that can be arbitrarily set.

SUMMARY OF THE INVENTION

Therefore, it is a primary object of the present invention to provide anovel content reproduction apparatus.

It is another object of the present invention to provide a contentreproduction apparatus capable of securely preventing an illegitimateuse of a content having an elapsed term of validity.

A content reproduction apparatus according to the present invention is acontent reproduction apparatus for reproducing a content having a termof validity, and characterized in that the apparatus comprises: a firstmeasuring means for measuring a first time period, which is from anon-operation of a main power until an off-operation thereof; a secondmeasuring means for measuring a second time period, which is from theoff-operation until the on-operation of a next time; a total sumcalculation means for calculating a total sum of the first time periodand the second time period; and an invalidating means for renderinginvalid a reproduction of the content when the calculated total sumexceeds the term of validity.

In the present invention, the first measuring means measures the firsttime period, which is from the on-operation of the main power until theoff-operation thereof, the second measuring means measures the secondtime period, which is from the off-operation of the main power until theon-operation thereof. Furthermore, the total sum calculation meanscalculates the total sum of the first time period and the second timeperiod, and the invalidating means renders invalid the content when thecalculated total sum exceeds the term of validity.

In another embodiment of the present invention, the content reproductionapparatus further comprises a back-up power, and the second measuringmeans includes a counting means that is driven by the back-up power andcounts a time period, and a calculating means for calculating the secondtime period on the basis of a count value by the counting means when theoff-operation is performed and a count value by the counting means whenthe off-operation of a next time is performed.

Furthermore, in still another embodiment of the present invention, thesecond measuring means includes a capacitor in which electric chargesare accumulated, a discharging means that causes the electric chargeaccumulated in the capacitor to be discharged in response to theoff-operation, a detecting means that detects a terminal voltage of thecapacitor in response to the on-operation, and a calculating means thatcalculates the second time period on the basis of the detected terminalvoltage.

According to the present invention, a time period, which is from theon-operation of the power until the off-operation thereof, and a timeperiod, which is from the off-operation until the on-operation of a nexttime, are measured in a sequential manner, thereby managing the term ofvalidity of the content on the basis of accumulated values of each ofthe measured time periods. Therefore, different from the above-describedprior art in which the term of validity of the content is managed on thebasis of the date of the calendar that is arbitrarily settable, thepresent invention is effective in surely preventing an illegitimate useof the content with an elapsed term of validity.

The above described objects and other objects, features, aspects andadvantages of the present invention will become more apparent from thefollowing detailed description of the present invention when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing schematic structure of a firstembodiment of the present invention;

FIG. 2 is an illustrative view showing a method of managing a term ofvalidity of a content in the FIG. 1 embodiment;

FIG. 3 is a flowchart showing an operation of a CPU in the FIG. 1embodiment;

FIG. 4 is a flowchart showing an operation of the CPU subsequent to theflowchart of FIG. 3;

FIG. 5 is a flowchart, which is different from FIG. 4, showing anoperation of the CPU subsequent to the flowchart of FIG. 3;

FIG. 6 is a block diagram showing schematic structure of a secondembodiment of the present invention; and

FIG. 7 is an illustrative view showing a clock circuit in detail in theFIG. 6 embodiment.

BEST MODE FOR PRACTICING THE INVENTION

A content reproduction apparatus 10 in this embodiment shown in FIG. 1is a portable type, for example, and an apparatus for reproducing audiodata such as voices or sounds, a music, or the like as a contentrecorded in a memory card 12. The memory card 12 is anattachable/detachable recording medium, and electrically connected to aCPU (Central Processing Unit) 18 via a memory interface 16 when attachedto a slot 14. It is noted that the audio data is recorded in the memorycard 12 in a compressed state according to a predetermined compressingformat such as an MP3 (MPEG-1 AUDIO Layer 3), an AAC (MPEG-2 AdvancedAudio Coding), or the like. Furthermore, a decoding software (decodingor decrypting program) for expanding the compressed audio data is alsorecorded in the memory card 12.

The CPU 18 fetches the audio data and the decoding software from thememory card 12, and supplies the fetched audio data and the decodingsoftware to a DSP (Digital Signal Processor) 22 when an instruction ofstarting the reproduction is applied from an operation key 20, to bemore specific, when a reproduction key (not shown) that constitutes theoperation key 20 is depressed.

The DSP 22 expands (decodes or decrypts) the audio data using thedecoding software supplied from the CPU 18, and inputs the expandedaudio data into a D/A converter 24. The D/A converter 24 converts theinput audio data into an analog audio signal. Then, the converted audiosignal is input into a headphone 30 via an output terminal 28 afterbeing amplified by an audio amplifier 26, and this reproduces the voicesor sounds (or music). It is noted that a suspension key (not shown) thatconstitutes the operation key 20 may be depressed in order to suspend areproduction operation. Then, an instruction of suspending thereproduction is applied from the operation key 20 to the CPU 18, and asa result, the CPU 18 controls the DSP 22 so as to suspend thereproduction operation.

It is noted that an RTC (Real Time Clock) circuit 32 for counting apresent time is connected to the CPU 18, and the CPU 18 realizes acalendar function on the basis of present time data supplied from theRTC circuit 32. Furthermore, a liquid crystal display 34 is connected tothe CPU 18, and various kinds of information are displayed in responseto operations of the CPU 18 on the display 34. Furthermore, an EEPROM(Electrically Erasable Programmable ROM) 36 is connected to the CPU 18,and a USB (Universal Serial Bus) terminal 40 is also connected theretovia an external interface 38.

Each of the circuits such as the CPU 18 is driven by power voltage Vccsupplied from a power source circuit 44 when a main power switch 42 isturned-on. Furthermore, the power source circuit 44 generates the powervoltage Vcc on the basis of direct current voltage DCV supplied from abattery 46. However, the RTC circuit 32 needs to be driven even during atime period that the power switch 42 is turned-off so that a back-upbattery 48 is used as a power source therefor. It is noted that theoff-operation of the main power switch 42 is controlled by the CPU 18.That is, the CPU 18 turns-off the main power switch 42 when aninstruction of turning-off the power is applied from the operation key20, more specifically, when a power-off switch constituting included inthe operation key 20 is depressed.

On the other hand, the audio data is downloadable from an Internet. Thatis, the Internet is accessed by a personal computer (not shown) so as totemporarily download desired audio data into the personal computer.Then, the personal computer (USB terminal of the personal computer, tobe exact) is connected to the USB terminal 40 after the downloading soas to transfer the audio data downloaded into the personal computer tothe CPU 18 via the USB terminal 40 and the external interface 38. Thisallows the CPU 18 to record the transferred audio data into the memorycard 12 via a memory interface 16. In addition thereto, it is possibleto fetch the audio data from a CD (Compact Disk), a DAT (Digital AudioTape), and the like.

Incidentally, the content reproduction apparatus 10 of this embodimentis provided with a function that renders the data having elapsed term ofvalidity Ta invalid (not reproducible) when reproducing the data havingthe term of validity Ta such as audio data for a trial listening. Inrealizing this function, in the content reproduction apparatus 10 ofthis embodiment, a so-called power-on time period Ton, which is from apoint of time ton that the main power switch 42 is turned-on until apoint of time toff, which is turned-off, and a so-called power-off timeperiod Toff, which is from a point of time toff that the main powerswitch 42 is turned-off until a point of time ton, which is turned-ononce again, are sequentially measured as shown in FIG. 2. Furthermore,an initial day of the term of validity of the audio data, that is, a dayto when the relevant audio data is recorded into the memory card 12 isused as a reference, for example, thereby calculating a total sum(accumulating value) T of the power-on time period Ton and the power-offtime period Toff from the reference day to. Then, the calculated totalsum T and the term of validity Ta of the audio data are compared witheach other, and then the audio data is rendered invalid when the totalsum T exceeds the term of validity Ta. It is noted that the data withrespect to the reference day to is stored in the above-described EEPROM36 in a state associated with the audio data.

In order that the term of validity of the audio data is thus managed onthe basis of the total sum T of the power-on time period Ton and thepower-off time period Toff, the CPU 18 carries out processes inaccordance with flowcharts of FIG. 3-FIG. 5. It is noted that a controlprogram for controlling an operation of the CPU 18 according to theseprocesses is stored in a memory not shown.

Referring to FIG. 3, when the main power switch 42 is turned-on, the CPU18 obtains present time data with respect to a present time (a time thatthe main power switch 42 is turned-on) ton from the RTC circuit 32 in astep S1. Next, data regarding the time toff that the main power switch42 is turned-off the last time is obtained from the EEPROM 36 in a stepS3. It is noted that when the main power switch 42 is turned-on for afirst time, data, that is, toff=0 is stored in the EEPROM 36 as dataregarding the time toff.

After thus obtaining the data regarding each of the time ton and thetime toff, the CPU 18 calculates a power-off time period Toff from atime difference of each of the time ton and the time toff (ton−toff) ina step S5. In addition, the data regarding the above-described total sumT is obtained from the EEPROM 36 in a step S7. It is noted that when theaudio data having the term of validity is recorded into the memory card12, data, e.g. T=0 is stored in the EEPROM 36 as data regarding thetotal sum T.

Then, a sum of the total sum T obtained in the step S7 and the power-offtime period Toff calculated in the step S5 is evaluated in a step S9,and the evaluated sum is recognized as a new total sum T. Furthermore,after resetting (Ton=0) a counter for measuring the power-on time periodTon in the step S11, counting the power-on time period Ton is started ina step S13. It is noted that the counter mentioned here is completelydifferent from the above-described RTC circuit 32, and may be structuredin a software manner by the CPU 18 or by a hardware circuit.

Furthermore, the CPU 18 determines whether or not the above-describedinstruction of turning-off the power is applied from the operation key20 in a step S15, and in a case that the instruction of turning-off thepower is not applied, it is determined whether or not the instruction ofstarting reproducing is applied from the operation key 20 in a step S17.If the instruction of starting reproducing is applied in the step S17,the CPU 18 proceeds to a step S19 shown in a flowchart in FIG. 4.

In the step S19, the CPU 18 determines whether or not the audio data tobe reproduced has the term of validity Ta. Then, in a case that theaudio data to be reproduced has the term of validity Ta, data regardingthe term of validity Ta is obtained from the memory card 12 in a stepS21. Next, the above-described total sum T and the term of validity Taare compared with each other in a step S23, and in a case that the totalsum T exceeds the term of validity Ta, the process proceeds to a stepS25 so as to render the audio data not reproducible. More specifically,a message indicating that the term of validity Ta is already elapsed isdisplayed on the display 34 without reproducing the audio data. Then,the CPU 18 returns to the step S15 in FIG. 3 after the process in thestep S25.

On the other hand, in a case that the total sum T does not exceed theterm of validity Ta in the step S23, the CPU 18 proceeds to a step S27so as to start reproducing the audio data. Furthermore, it is determinedwhether or not the above-described instruction of suspending thereproduction is applied from the operation key 20 in a step S29, and ina case that the instruction of suspending the reproduction is notapplied, it is determined whether or not the reproduction of the audiodata is ended in a step S31. In the step S31, in a case that thereproduction of the audio data is not ended, the process returns to thestep S29, and in a case that the reproduction is ended, the processreturns to the step S15 in FIG. 3. It is noted that if the instructionof suspending the reproduction is applied from the operation key in thestep S29, the CPU 18 proceeds to a step S33 so as to herein suspend thereproduction operation, and thereafter, the process returns to the stepS15.

Upon receipt of the instruction of turning-off the power in the stepS15, the CPU 18 proceeds to a step S35 shown in a flowchart in FIG. 5.Then, in the step S35, present time data regarding the present time(time that received the instruction of turning-off the power) toff fromthe RTC circuit 32 is obtained, and the data regarding the obtained timetoff is stored into the EEPROM 36 in a step S37.

Furthermore, a sum of the above-described total sum T and the power-ontime period Ton measured until a present time (until a point of timethat the instruction of turning-off the power is received) is evaluatedin a step S39, and the evaluated sum is recognized as a new total sum T.Moreover, after storing the data regarding the total sum T into theEEPROM 36 in a step S41, the process ends a series of the operations byactually turning-off the main power switch 42 in a step S43.

As described above, according to the content reproduction apparatus 10of this first embodiment, the power-on time period Ton and the power-offtime period Toff are sequentially measured, and then the term ofvalidity Ta of the audio data is managed on the basis of the total sum Tof each of the measured time periods Ton and the Toff. Therefore,different from the above-described prior art in which the term ofvalidity Ta is managed on the basis of a date of a calendar that isarbitrarily set, it is possible to strictly manage the relevant term ofvalidity Ta, and surely prevent an illegitimate use of the audio datahaving an elapsed term of validity Ta.

It is noted that with respect to the power-off time period Toff, whichis calculated on the basis of the data regarding the time ton and toffobtained from the RTC circuit 32 so that it is seemingly considered thatthe power-off time period Toff is arbitrarily changeable by(illegitimately) operating the RTC circuit 32. However, since it is notpossible to operate the RTC circuit 32 when the power is turned-off, anexact calculation is possible with respect to the power-off time periodToff even if a clock time by the RTC circuit 32 is not exact.

Next, referring to FIG. 6, the content reproduction apparatus 10 of thesecond embodiment is provided with a clock circuit 50 to be connected tothe CPU 18 in place of the RTC circuit 32 and the back-up battery 48 instructure of the first embodiment shown in above-described FIG. 1. Withrespect to the structure other than this, the same is applied as in thefirst embodiment so that detailed descriptions are omitted by applyingidentical numerals to these similar portions as in FIG. 1.

In the second embodiment, the power-off time period Toff is measured byutilizing a discharge characteristic of a capacitor 52 described laterthat constitutes the clock circuit 50. In this point, the secondembodiment is different from the first embodiment in that the power-offtime period Toff is measured by utilizing the time ton and the toffmeasured by the RTC circuit 32.

Referring to FIG. 7, the above-described capacitor 52 is connected inbetween the circuit voltage Vcc and a grounding electric potential (GND)via a switching circuit 54. An operation of turning-on/off the switchingcircuit 54 is controlled by the CPU 18. In addition, a resistor 56 isconnected at both ends of the capacitor 52. Furthermore, a voltage Vbetween the both ends of the resistor 56 (capacitor 52) is input into anA/D converter 60 via a buffer amplifier 58, and data digitalized by theA/D converter 60 is supplied to the CPU 18.

In structure of this FIG. 7, electric charges accumulated in thecapacitor 52 are to be discharged by turning-off the switching circuit54 after charging the capacitor 52 by turning-on the switching circuit54, for example. In this case, the voltage V between the both ends ofthe resistor 56 is expressed by a following Equation (1).V=E·exp(−t/CR)[V]  (1)

It is noted that E is voltage between the both ends of the capacitor 52at a time of starting the discharge (t=0), and E≈Vcc. In addition, C isa capacity of the capacitor 52, and R is a resistance value of theresistor 56. Furthermore, an input impedance of the buffer amplifier 58is infinite (∞).

Moreover, if Equation (1) is developed into an equation regarding a timet, a following Equation (2) is obtained.t=CR(log E−log V)[s]  (2)

Herein, in view of a fact that each of the capacity C of the capacitor52, the resistance value R of the resistor 56, and the voltage E (≈Vcc)between the both ends of the capacitor 52 at a start of discharging areknown, it is possible to recognize the time period t from a time thatthe switching circuit 54 is turned-off by measuring the voltage Vbetween the both ends of the capacitor 54. Therefore, as for anoperation of the CPU 18, the switching circuit 54 is to be turned-offafter temporarily turning-on the switching circuit 54 when theaforementioned instruction of turning-off the power is applied from theoperation key 20 (at a point of time toff). Next, the voltage V isdetected when the main power switch 42 is turned-on (at a point of timeton), thereby evaluating a discharging time period t by substitutingEquation 2 for the detected voltage V, and consequently, the evaluateddischarging time period t is specified as the power-off time periodToff.

This allows to calculate the power-off time period Toff by relativelysimple circuit structure as shown in FIG. 7 not using theabove-described RTC circuit 32. It is noted that a capacitor having alarger capacity C is preferably used as for the capacitor 52.Furthermore, a resistor value having a larger resistance value R ispreferably used as for the resistor 56. It is noted that the dischargingtime period t may be evaluated under conditions of a natural discharge,not using the resistor 56.

It is noted that although in each of the above-described embodiments,descriptions are made regarding a case that the audio data is reproducedas a content, the present invention may be applied to an apparatus forreproducing other contents such as image data, for example. In addition,the content reproduction apparatus 10 is not necessarily a portabletype, that is, a type fixed on a desk, a predetermined rack, or the likemay be appropriate, for example.

Furthermore, although the memory card 12 is used as a means forrecording audio data, this is not always limited thereto. Anotherrecording medium such as a magnetooptical disk, a magnetic tape, or thelike may be used, for example.

In addition, an error message is to be displayed on the display 36 inthe step S57 in FIG. 5. However, the relevant error message may beoutput in an audible manner such as ringing a buzzer, outputting voices,and so on, for example, in place of (or, concurrently with) a visualmanner, which displays the error message.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

1. A content reproduction apparatus for reproducing a content having a term of validity, comprising: a first measuring means for measuring a first time period, which is from an on-operation of a main power until an off-operation thereof; a second measuring means for measuring a second time period, which is from said off-operation until said on-operation of a next time; a total sum calculation means for calculating a total sum of said first time period and said second time period; and an invalidating means for rendering invalid said content when said total sum exceeds a term of validity.
 2. A content reproduction apparatus according to claim 1, further comprising a back-up power source, wherein said second measuring means includes a counting means that is driven by said back-up power source and counts a time period, and a calculating means for calculating said second time period on the basis of both a count value by said counting means when said off-operation is performed and a count value by said counting means when said on-operation of a next time is performed.
 3. A content reproduction apparatus according to claim 1, wherein said second measuring means includes a capacitor in which electric charges are accumulated, a discharging means that causes said electric charges accumulated in said capacitor to be discharged in response to said off-operation, a detecting means that detects a terminal voltage of said capacitor in response to said on-operation, and a calculating means that calculates said second time period on the basis of said terminal voltage as detected. 